That should work, except: do you like the taste of cooked lettuce? For me, it's ok on its own, but I often don't like it in combination with other things. I once ordered lobster sashimi at Fugakyu, and they used the head in miso soup. That sounded like a terrific idea to me, until they served it, and I saw it had lettuce. For me, that ruined what should have been a great soup. I finished it to avoid waste, but as I recall, it wasn't even good.